Preparation of magnetic ion-exchange resins by the suspension polymerization of styrene with magnetite

Magnetic polymer microspheres composed of magnetite, styrene, and divinylbenzene were prepared by suspension polymerization to produce magnetic ion-exchange resins (MIEXs). The magnetite was grafted with oleic acid to improve the magnetic properties of the MIEXs and to prevent the magnetite from flushing out of the MIEXs. The shape and magnetic properties of the magnetic microspheres were investigated with scanning electron microscopy and vibrating-sample magnetometry. The average diameter of the prepared magnetic polymer microspheres was about 219 mum. The two types of MIEXs were prepared, magnetic cation-exchange resins (MCEXs) and magnetic anion-exchange resins (MAEXs). MCEX was prepared by sulfonation of magnetic polymer microspheres, and MAEX was made by a quaternization reaction with triethylamine of chloromethylated magnetic polymer microspheres. With diffuse-reflectance Fourier transform infrared spectroscopy, elemental analysis, and acid-base titration, the degree of substitution and ion-exchange capacity of the MIEXs were assessed. The efficiency of each MCEX and MAEX for the purification of contaminated water was examined with Co2+ and NO3- solutions, respectively. (C) 2003 Wiley Periodicals, Inc.